A variety of different shoe constructions are used by the footwear industry. For the most part, each shoe construction has characteristics that make it particularly well-suited for specific applications. For example, some shoe constructions are selected for their durability, others for their flexibility and comfort, while still others are selected for their aesthetic appeal.
In general, shoe construction typically involves a number of manufacturing operations or steps. Normally, a significant number of manufacturing operations generally results in a more expensive shoe. In a market where competitive price is often desired, there appears to be a need to make shoes in an efficient manner. Conventionally, a shoe construction may involve an upper being stitched to a forepart of an outsole by a hand stitch and the rearpart of the outsole may be attached to the upper by adhesive after a lasting operation. Lasting is typically where a last, an object which simulates a user's foot, is inserted into the upper and the upper is often then pulled taught around the last and secured to a tuck, which is removably attached to the bottom of the last. The tuck generally provides a structure that is adhered to the rearpart of the outsole, which in turn results in the upper being secured to the outsole in the rearpart of the shoe. Without a tuck, it may be difficult to secure the upper to the outsole.
A traditional insole is often wrapped with a wrapper around its peripheral edge to help prevent the edge of the insole from wear. The insole with the wrapper is then typically secured to the tuck or outsole. In a separate operation, a socklining may then be adhered directly to the top of the insole for providing a surface adapted to receive a user's foot because the insole's surface is often coarse.
Another shoe construction, cementing, also often involves a number of manufacturing operations. Cementing components of a shoe, such as the upper to the outsole, typically involves a surface preparation step where the surfaces to be cemented, or glued, are clean of debris and readied, which may also include roughening. Further, there may be an application step where the cement is applied to the surfaces. This step may also involve measuring and evenly distributing the glue over the surface.
Further, there may be a pressing step where the surfaces are pressed together. Pressing is believed to reduce air that may be trapped between the surfaces and enhances adhesion. Pressing may also include aligning the surfaces so that the peripheries of the components are flush with one another.
Additionally, once the components are pressed together, cementing often requires a waiting period for the cement to cure, or dry. Generally, not only does cementing involve some or all of the above mentioned manufacturing operations, it also involves time, particularly the curing time.
It is believed that the number of steps and time involved, especially if user intervention is required, negatively affects cost and efficiency. The cementing process may be further complicated if the surfaces to be glued are uneven or difficult to reach.
U.S. Pat. No. 4,369,589 to Summey (“Summey”) and U.S. Pat. No. 3,821,827 to Nadler (“Nadler”) appear to disclose a shoe having cement or glue to secure the upper to the midsole or outsole. Summey seems to disclose the pressing and aligning operations as well as user intervention described above. Summey also seems to disclose an insole as a part of the shoe.
U.S. Pat. No. 4,685,223 to Long (“Long”) seems to relate to a shoe having an upper, socklining margin, and outsole sewn together. A cushion is enclosed by the socklining and the socklining upper is secured to the upper and outsole by the stitch. Hence, the upper is not sewn directly to the outsole. Moreover, although Long discloses a recess in the outsole, it appears to be on a side of the outsole, which may increase stress on the stitch since the stitch seems to be placed in a generally tortuous orientation where the stitch extends vertically downward from the upper and turns generally horizontal out the side of the outsole. Increasing stress on the stitch may contribute toward the stitch's failure.
U.S. Pat. No. 6,029,301 by Issler (“Issler”) appears to disclose a shoe having a channel in the bottom surface of the outsole and an upper in contact with a top surface of the outsole, where a stitch passes from the upper to the channel without passing to the bottom surface of the outsole. The channel seems to protect the stitch from wear due to contact between the bottom surface and the ground. However, because the channel appears to be placed within a confined space, dirt, sand, or other debris may get trapped in the space and, as a result, cause wear to the stitch. Moreover, the socklining seems to be adhered to the outsole or cushion, where adhering or gluing the socklining often increases the number of operations and/or cost for constructing the shoe. Furthermore, should the gluing operation prove to be messy, clean up operations may be needed to clean the excess glue.
The sockliner of Issler may be modified to be merely placed on top of the outsole or cushion without adherence. However, in these situations, the sockliner is often attached to a structure, such as a tuck or insole, and the entire unit is then placed on top of the outsole or cushion. Without a tuck or insole, the sockliner may not remain on top of the outsole or cushion as it may tend to slide around due to its lack of structural integrity.
What is desired, therefore, is a shoe that may be constructed in a more efficient manner, including reduced manufacturing costs and less manufacturing operations. What is also desired is a shoe that is efficiently manufactured without sacrificing comfort or aesthetic appeal.